# 1985 York
Trials to investigate the deformation and buckling behaviour of HDPE pipes with profiled outer wall and smooth bore are reported. Results show that the deformation and stability check can be carried out in the same way as for solid-wall pipes. However, an additional check on circumferential compressive stresses is required for the relatively thin-walled profile. These compressive stresses must be lower than the permissible buckling stress of the profile and the permissible compressive stress of the material.